Being the PR person for a cork producer would not be easy. To promote cork as being environmentally friendly in these times of worry about climate change and global warming is a good angle to pursue. Thus the Portuguese cork producer Amorin took the step to commission a report from Pricewaterhouse Coopers/Ecobilan which is titled "Evaluation of the environmental impacts of Cork Stoppers versus Aluminium and Plastic Closures-Analysis of the life cycle of Cork, Aluminium and Plastic Wine Closures."

Not surprisingly, for the product of a slow growing tree that captures carbon dioxide and stores the carbon component, it finds cork is more environmentally friendly than alternatives. Or as the widely publicised summary reads; "The study found that CO2 emissions during the life cycle (production, transport, associated packaging and end of life) of 1,000 cork stoppers amounts to 1,533g of carbon dioxide equivalent (CO2e) over 100 years, while the figure for plastic stoppers is 14,833g of CO2e per 1,000 stoppers and for screwcaps 37,172g of CO2e per 1,000 stoppers."

I do not have the time to do a serious review of this very good paper which goes to 127 pages as it would take this non expert many days to catch up with the current methodology and science. For example the summary of what they attempted to do says: "To evaluate the potential impacts of natural and synthetic wine closures on the environment, the
survey proposed seven indicators: non-renewable energy consumption; water consumption;
emission of greenhouse gases; contribution to atmospheric acidification; contribution to the
formation of photochemical oxidants (ozone layer depletion); contribution to the eutrophication of surface water and production of solid waste."

And to give you an idea of how fraught with difficulty such a study is they state that for aluminium: "The process for the production of aluminium closures from the aluminium sheets was not included, due to lack of information available in the public domain." This may be only one small step though it reminded me of an Economist article several years ago explaining why Tesco was having so much trouble coming to any meaningful statement for its customers of the 'carbon footprint' of every item sold. I think they have abandoned this project.

What did catch my eye and is a bit puzzling is the following comment: "Performance of the different closures as wine closures: Failure rates for all types of closures - cork, aluminium or plastic - have not been assessed using strictly scientific methodology. As a result, screwcap-induced reduction, cork-induced TCA or plastic-induced oxidation are often mentioned in international media as commonly occurring faults that can negatively impact wine; but no hard quant data exists that details such failure rate for any of the closures under assessment in this LCA. In the absence of fact-based knowledge, the functional unit selected does not include this information. When this information is available for the three types of closures, it will be possible to make a new survey considering a different functional unit and including this information."

The reason there has been such an accelerating move away from cork is because of the high rate of TCA tainted wine associated with cork and with older wines, random oxidation. It is true that the sudden widespread use of aluminium closures found many winemakers uncertain as to how to prepare wine for bottling and there were reductive problems (unpleasant aromas). In advanced wineries and bottling halls these are now largely eliminated.

Also since the bottle is not included in the study, and may make up 90% (?), of the final carbon dioxide equivalent of the wine we buy, the gap between the closures becomes less meaningful.

Above all though when 5% - 7% of the bottles you buy sealed with cork are made defective from the closure it is time to abandon this method. That is what is happening and I see no turning back.

With the climate problems that appear to be besetting us I find it a strange tangent for knowledgeable consumers to embrace the fantasy that worrying about how a wine is sealed makes the slightest difference to helping the climate. Do we no longer eat meat because sheep and cows belch? (see Kangaroos to the rescue, New Scientist 27th December, 2008).

Friday, 20th August, 2004

Thursday, 19th August, 2004

Wednesday, 23rd June, 2004

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